Cream together shortening, baking soda, vinegar, sugar and eggs. Make a paste with cocoa and food coloring and add to creamed mixture. Mix salt and vanilla with buttermilk. Add alternately with flour to creamed mixture. Mix with a spoon, do not beat. Bake 30 minutes at 350 degrees.
Cook flour and milk until thick, stirring constantly. Set aside until fully cooled. Beat sugar, butter and vanilla together and add it to the milk mixture. Beat until it is fluffy like whipped cream and spread evenly on cake.
Not a NESTLÉ®-tested recipe.